NAME

cupmtr - overwrite the general complex M-by-N matrix C with   SIDE = ’L’ SIDE = ’R’ TRANS = ’N’

SYNOPSIS

SUBROUTINE CUPMTR( SIDE, UPLO, TRANS, M, N, AP, TAU, C, LDC, WORK, INFO )

CHARACTER SIDE, TRANS, UPLO

INTEGER INFO, LDC, M, N

COMPLEX AP( ∗ ), C( LDC, ∗ ), TAU( ∗ ), WORK( ∗ )

#include <sunperf.h>

void cupmtr(char side, char uplo, char trans, int m, int n, complex ∗cap, complex ∗tau, complex ∗cc, int ldc, int ∗info) ;

PURPOSE

CUPMTR overwrites the general complex M-by-N matrix C with TRANS = ’C’:      Q∗∗H ∗ C       C ∗ Q∗∗H
 
where Q is a complex unitary matrix of order nq, with nq = m if SIDE = ’L’ and nq = n if SIDE = ’R’. Q is defined as the product of nq-1 elementary reflectors, as returned by CHPTRD using packed storage:
 
if UPLO = ’U’, Q = H(nq-1) . . . H(2) H(1);
 
if UPLO = ’L’, Q = H(1) H(2) . . . H(nq-1).
 

ARGUMENTS

SIDE (input) CHARACTER∗1
= ’L’: apply Q or Q∗∗H from the Left;
= ’R’: apply Q or Q∗∗H from the Right.

UPLO (input) CHARACTER∗1
= ’U’: Upper triangular packed storage used in previous call to CHPTRD; = ’L’: Lower triangular packed storage used in previous call to CHPTRD.

TRANS (input) CHARACTER∗1
= ’N’:  No transpose, apply Q;
= ’C’:  Conjugate transpose, apply Q∗∗H.

M (input) INTEGER
The number of rows of the matrix C. M >= 0.

N (input) INTEGER
The number of columns of the matrix C. N >= 0.

AP (input) COMPLEX array, dimension
(M∗(M+1)/2) if SIDE = ’L’ (N∗(N+1)/2) if SIDE = ’R’ The vectors which define the elementary reflectors, as returned by CHPTRD.  AP is modified by the routine but restored on exit.

TAU (input) COMPLEX array, dimension (M-1) if SIDE = ’L’
or (N-1) if SIDE = ’R’ TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CHPTRD.

C (input/output) COMPLEX array, dimension (LDC,N)
On entry, the M-by-N matrix C. On exit, C is overwritten by Q∗C or Q∗∗H∗C or C∗Q∗∗H or C∗Q.

LDC (input) INTEGER
The leading dimension of the array C. LDC >= max(1,M).

WORK (workspace) COMPLEX array, dimension
(N) if SIDE = ’L’ (M) if SIDE = ’R’

INFO (output) INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value

SunOS WorkShop_5.0  —  Last change: 10 Dec 1998